1. Field of the Invention
This invention relates to a smoke suppressant composition of poly(vinyl halide) and a member selected from copper carbonate, cobalt carbonate, or mixtures thereof.
2. Description of Prior Art
Smoke, and especially dense smoke, is a hazard during a fire since the smoke can obscure means of escape and hamper firefighting measures. Hence, it is desirable to develop building materials that emit reduced amounts of smoke during combustion as an added safety feature. The composition of the present invention meets this requirement.
The commercially available poly(vinyl chloride) smoke suppressant, ferrocene (called FE-55 and manufactured by Arapahoe Chemical Co., Inc.), has the disadvantage of being expensive and volatile (vapor pressure is 2.6 mm Hg at 100.degree. C.) at typical milling temperatures of 130.degree.-145.degree. C. Because of the high volatility of FE-55, in laboratory work it is necessary to prepare the FE-55 formulations in a closed system such as a Banbury mixer or Brabender Plasticorder. The use of an open system such as a roll-mill results in significant losses of the FE-55. Arapahoe Chemical Company has reported that FE-55 is not suitable for PVC with more than 10 phr (parts per hundred parts resin) plasticizer since losses of FE-55 due to volatility will occur on long-term aging.
Although copper and cobalt compounds are known in the prior art as smoke suppressants for poly(vinyl halides), the copper and cobalt carbonates of this invention were not found. Some of the prior art copper and cobalt compounds found as smoke suppressants for poly(vinyl halide) are: copper oxides, copper sulfides, cobalt salts, ammonium molybodcobaltate, cobalt chloride, cobalt acetate and cobalt trimellitate. The compositions of this invention give superior smoke suppression results when compared to the prior art compositions.